The present invention relates to the provision of network services, and particularly although not exclusively to the provision of network services in circuit switched communications networks.
Prior art time division multiplexed (TDM) telephone systems provide network services to individual calls by internally redirecting those calls within an exchange to one or more individual network service provider equipment items which may be co-located in the exchange, either within a switch, or within a rack or row of racks associated with a switch. Network service provider devices provide services to calls passing through an exchange. Such devices may include network announcers, intelligent peripheral devices, universal tone receivers (UTRs) and universal tone generators (UTGs). Network announcers may comprise simple announcement devices for sending messages such as xe2x80x9call international lines are busyxe2x80x9d or the like. Such machines have historically developed from simple analogue devices for playing pre-recorded messages, more recently to digital devices for playing pre-stored messages. A universal tone generator provides dial tones to a call, and a universal tone receiver detects tone dial digits from a call.
Referring to FIG. 1 herein, there is illustrated schematically a general architectural overview of a prior art exchange comprising a conventional prior art TDM switch 100, a network announcer device 101, an intelligent peripheral device 102, and a universal tone receiver/universal tone generator (UTR/UTG) device 103. Typically, network service provider components 101-103 may be co-located with the TDM switch within an exchange building in an array of racks as illustrated schematically in FIG. 2 herein. A conventional circuit switched TDM call comprises first and second channels between an originating source device, eg a first telephone device, and a receiving destination device, eg a second telephone device. Each circuit carries traffic data, eg voice or fax/modem traffic data in a first direction on the first channel from the first device to the second device and in a second direction on the second channel from the second device to the first device. A call on an incoming (originating) TDM circuit or trunk may be received by TDM switch 100 at an input port 104 of the switch, routed through the switch via one or more network service provider devices associated with the switch and routed through an output port 105 of the switch. Network services are provided by network service modules comprising for example the network announcer, intelligent peripheral, or UTR/UTG.
In the conventional network, such network services are required at many points in the network. For example in prior art legacy networks, when a number is dialed, parts of the number are echoed from exchange to exchange across the network. Each exchange in a path has to separately recognize it""s portion of the dialed number and route the call on that basis. This process incurs delays at every exchange the call passes through. In legacy networks, it is common that some types of service provider for example the UTR/UTG are provided at each exchange in the network, whilst other types of service provider eg the network announcer or intelligent peripheral may appear only at specified places in the network and not on every exchange.
In each case, in prior art legacy networks the network service provider comprises a discrete card or rack of equipment within an exchange. The exchange, when it receives a call either directly from a subscriber or from an incoming trunk recognizes dialed digits or an off-hook signal, and internally switches the call to an appropriate service provider component. This incurs delays throughout the network.
Referring to FIG. 3 herein, there is illustrated components of an exchange which detect a call and connect the call to a UTR and UTG. As a call is built up from originating source to destination, when a phone 300 goes off hook, a seize detect element 301 of a local exchange 302 detects that the phone has gone off hook. This causes an electronic connection of the call to a universal tone generator 303 which applies a dial tone back to the call.
In the prior art switches, the whole call must be switched entirely through the internal switch network. Each switch takes time to re-direct the call to the appropriate network service provider component. In practice, the physical media used to connect each rack and component is electrical or optical cabling using T1/E1 or higher rate trunks. Where higher rates are used there is an inefficiency in re-multiplexing the data to a higher rate and then de-multiplexing data within the relevant service provider function. Normally, the whole speech path of a call has to be passed to the relevant service provided component and that component then has to pass the speech path back to the switching fabric of the switch for completing a path to the outgoing trunk, thereby incurring delays at the switch in connecting a call to the network service provider devices.
One object of the specific implementations of the present invention is to avoid the delays associated with switching of a complete call through an internal switching network when providing network services.
Another object of specific implementations of the present invention is to avoid rebuilding internal switch paths for provision of network services to a call.
According to one aspect of the present invention that is provided a circuit switched communications nodal architecture capable of providing a plurality of network services to a plurality of time division multiplexed channels, said architecture comprising:
a plurality of conversion means for converting a plurality of said time division multiplex channels to a plurality of packet stream channels;
a plurality of interface means for interfacing between said plurality of time division multiplixed channels, and said plurality of conversion means;
a plurality of switching means each capable of switching said packet stream channels over a plurality of through connections through said switching means; and
a plurality of peripheral devices, each capable of providing network service signals; wherein
each said peripheral device communicates with at least one said through connected channel by means of at least one further connecting channel connecting said through connected channel and said peripheral device.
The through connected channel preferably extends directly through said switching means without being routed through a said peripheral device.
The connecting channel preferably comprises at least one packet stream passing between the through channel and said peripheral device.
The connecting channel preferably carries data duplicated from said through connected channel, said duplicated data being transmitted to said peripheral device.
Traffic data carried on a said through channel may be replicated and broadcast to a plurality of said peripheral devices.
A time division multiplexed circuit comprising first and second channels may be converted by said conversion means into first and second packet stream channels, and each of said first and second packet stream channels maybe replicated to produce first and second replicated packet stream channels which are communicated to a said peripheral device.
A said peripheral device may comprise a network announcer device, a universal term receiver device, a universal term generator device, an intelligent peripheral device, or a like device capable of providing network service data to a one or a plurality of communications circuits extending across the circuit.
According to a second aspect of the present invention there is provided a method of providing network services to a communications circuit between a source device and a destination device, said circuit having a time division multiplexed channel portion, said method comprising the steps of:
converting said time division multiplexed channel portion of said circuit to at least one packet stream channel;
passing said packet stream channel through at least one switch fabric; and
providing a connecting channel between said through packet stream channel and a network service provider device, for communicating data between said packet stream channel and said network service provider device.
Said method preferably comprises the step of duplicating a stream of packets carried on said through packet stream channel; and
supplying said duplicated packets to said network provider device via said connecting channel.
Said method may further comprise the steps of;
generating service data at said service provider device;
incorporating said service data into a plurality of packets;
incorporating said packetized service data into a channel of said circuit.
Said method may comprise the steps of;
generating service data;
incorporating said service data into a plurality of packets;
sending said packetized service data over said connecting channel connecting an end to end channel of said circuit between a source device and said destination device with a said network service provider device.
Said method may comprise the steps of;
replicating a set of data packets comprising said through channel; and
supplying said stream of replicated data packets to a said network service provider device.
According to a third aspect of the present invention there is provided a method of providing services to a plurality of communications circuits carrying traffic data, each said circuit comprising a time division multiplexed portion and a packetised portion, said method comprising the steps of;
converting said traffic data from a time division multiplexed mode to a packetized mode;
inputting a stream of packets containing said traffic data to a switching element;
transporting said packet stream across said switching element over a direct channel between an input and an output of said switching element;
generating a service data packet stream containing service data providing a network service;
inputting said service data packet stream to said switch element; and
incorporating said service data packets into said packet stream containing service data.
The invention includes an exchange apparatus in a communications network, said apparatus capable of providing network services to a plurality of communications circuits, said exchange apparatus comprising;
a switch element; and
at least one network service provider device capable of generating network service data,
wherein said switch element is capable of replicating a data carried on said circuit and directing said replicated data to said network service provider device, and
said switching means is capable of incorporating service data generated by said service provider device into said communications circuit.
The exchange apparatus preferably further comprises conversion means capable of converting between a time division multiplexed signal channel of a said communications circuit and a packet stream signal channel of said communications circuit.
A said switch element preferably comprises a plurality of inputs and outputs, and is adapted to carry said communications circuit directly across said switch between a said input and a said output, said service data being incorporated into said communications circuit between said input and said output.
A said switch element preferably has a plurality of inputs and outputs, and is adapted to transfer said communications circuit between a said input and a said output in the form of a stream of packetized signals, wherein said switch element operates to replicate the said stream of packetized signals and route said replicated packetized stream to a said service provider device.
According to a fourth aspect of the present invention there is provided a circuit switch communications network comprising:
a plurality of switch fabrics;
a plurality of network service provider devices;
a plurality of conversion means converting between a time division multiplex mode and a packet stream mode;
a time division multiplexed access network;
wherein said communications network is architecturally arranged such that said plurality of switch fabrics are distributed at a plurality of geographically disparate sites;
said plurality of network service provider devices are arranged amongst said plurality of geographically separated sites;
a plurality of end to end through circuits are created across said communications network each said through circuit having a time division multiplexed portion and a packet stream portion;
said plurality of conversion means operate to convert between said time division multiplexed access portions and said packet stream portions; and
a said through circuit communicates with a said network service provider device by means of a connecting channel between said through circuit and said network service provider device.
The invention includes a circuit switched communications network capable of providing a plurality of network services to a plurality of time division multiplexed channels, said communications network comprising:
a plurality of conversion means for converting a plurality of said time division multiplex channels to a plurality of packet stream channels;
a plurality of interface means for interfacing between said plurality of time division multiplexed channels, and said plurality of conversion means;
a plurality of switching means each capable of switching said packet stream channels over a plurality of through connections through said switching means; and
a plurality of peripheral devices, each capable of providing network service signals; wherein
each said peripheral device communicates with at least one said through connected channel by means of at least one further connecting channel connecting said through connected channel and said peripheral device.